Load port

ABSTRACT

A load port including: a base as part of a wall partitioning a transportation space from an external space; an opening provided to the base; a door configured to open and close the opening and securing a lid to, and releasing a lid from, a container containing contents; and a first seal member for sealing the space between the base and the container. At least some of the container-side end surface of the door is located nearer to the transportation space than the container-side end part of the first seal member. The load port can keep a surrounding space clean when a FOUP is connected to a casing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityunder 35 U.S.C. § 120 from U.S. application Ser. No. 15/750,376 filedFeb. 5, 2018, the entire contents which are incorporated herein byreference. U.S. application Ser. No. 15/750,376 is a National Stage ofPCT/JP2016/070568 filed Jul. 12, 2016, which claims the benefit ofpriority under 35 U.S.C. § 119 from Japanese Application No. 2015-154593filed Aug. 4, 2015.

TECHNICAL FIELD

The present invention relates to a load port having a door operationsystem capable of circulating gas in a wafer conveyance chamber, withoutexposing a transported wafer to outside air.

BACKGROUND ART

Traditionally, a wafer as a substrate is subjected to various processingsteps to manufacture semiconductors. With further advancement in higherintegration of elements and miniaturization of circuits in recent year,there is a demand for maintaining a high cleanliness level ofenvironment surrounding wafers, so as to avoid adhesion of particles ormoisture on the surface of a wafer. Further, in order to avoid a changein the characteristics of the surface, such as oxidation of a wafersurface, a wafer-surrounding environment is made an atmosphere ofnitrogen which is an inert gas, or made vacuum state.

To properly maintain the atmosphere around the wafer, the wafers areplaced inside a sealed storage pod called FOUP (Front-Opening UnifiedPod), and nitrogen is filled in the inside thereof of the pod. Further,for transferring wafers between a processing apparatus which processeswafers and the FOUP, an EFEM (Equipment Front End Module) is used. TheEFEM structures a wafer conveyance chamber which is substantially closedinside a casing. One of wall surfaces facing each other has a load portthat functions as an interface unit with the FOUP, and the other wallsurface is connected to a load lock chamber which is a part of theprocessing apparatus. Inside the wafer conveyance chamber, a waferconveyance apparatus configured to convey wafers is provided. Wafers areloaded and unloaded between the FOUP connected to the load port and theload lock chamber.

As a load port, for example, PTL 1 suggests a structure in which thedoor unit protrudes from the casing towards the FOUP.

CITATION LIST Patent Literature

[PTL 1] Japanese Unexamined Paten Publication No. 2014-112631

SUMMARY OF INVENTION Technical Problem

In the load port described in PTL 1 however, the door unit protrudingfrom the casing contacts the FOUP, when the FOUP is moved closer to thecasing. This contact may cause scattering of fragments, thuscontaminating the space surrounding the EFEM.

In view of the above, the present invention is made to address the aboveissues, and it is an object of the present invention to provide a loadport that keeps the surrounding space clean, when an FOUP is connectedto a casing.

Solution to Problem

The load port related to the present invention includes:

-   -   a base constituting a part of a wall separating a conveyance        space from an external space;    -   an opening portion provided in the base,    -   a door configured to open and close the opening portion and to        fix and release a lid member with respect to a container        accommodating therein an article;    -   a first seal member for sealing between the base and the        container;    -   wherein    -   a container-side end surface of the door is at least partially        positioned closer to the conveyance space than a container-side        end portion of the first seal member.

With this load port, even if the lid member of the container is inflatedtowards the base, the container-side end surface of the door ispositioned closer to the conveyance space than the container-side endportion of the first seal member, when the container is attached to theopening portion. Therefore, the lid member and the door do not contacteach other. This prevents the lid member from contacting the door andscattering fragments, and keeps the space surrounding the load portclean. Further, it is possible to restrain an impact of contact fromstirring up the dusts on the door, or from shaking the container to stirup the dusts at the bottom portion of the container or deviate theposition of accommodated article from the proper position.

The load port related to the present invention includes:

-   -   a clamp unit configured to press the container toward the base        while the container is attached to the opening, wherein    -   a container-side end surface of the door is at least partially        positioned closer to the conveyance space than a container-side        end portion of the first seal member which is pressed towards        the base by the container clamped by the clamp unit.

In the load port, the container-side end surface of the door is at leastpartially positioned closer to the conveyance space than thecontainer-side end portion of the first seal member which is clamped andpressed against the base. Therefore, it is possible to reliably preventcontact of the lid member with the door, while the container is attachedto the opening portion.

The load port related to the present invention includes:

-   -   an end surface of the door, which is to face the container, has        a recess depressed towards the conveyance space.

With the load port, it is possible to reliably prevent the lid memberfrom contacting the door, even if the lid member of the container isinflated towards the base.

In the load port related to the present invention:

-   -   the shape of the recess corresponds to an inflated surface of        the lid member inflated by increasing the pressure inside the        container.

In the load port, the shape of the recess corresponds to the inflatedsurface of the lid member which is inflated by increasing the pressureinside the container. Therefore, the lid member and the door arereliably kept from contacting each other, even if the container inflatesin various shapes.

The load port related to the present invention includes:

-   -   a second seal member for sealing between the base and the door,        wherein    -   a container-side end surface of the door is entirely positioned        closer to the conveyance space than a container-side end portion        of the first seal member.

In the load port, a container-side end surface of the door is entirelypositioned closer to the conveyance space than a container-side endportion of the first seal member. Thus, while the lid member and thedoor are reliably kept from contacting each other, sealing by the secondseal member between the base and the door unit is maintained.

The load port related to the present invention includes:

-   -   a second seal member for sealing between the base and the door;    -   a sealed space defined by at least the first seal member, the        second seal member, the lid member, and the door while the        container is in contact with the opening portion via the first        seal member;    -   a first gas injection unit configured to inject a gas into the        sealed space; and    -   a first gas discharge unit configured to discharge a gas from        the sealed space.

The load port includes: the first gas injection unit configured toinject gas into the sealed space formed between the container and thedoor, while the container is in contact with the opening portion via thefirst seal member, i.e., while the container is attached to the openingportion, and the first gas discharge unit configured to discharge gasfrom the sealed space. With this, it is possible to remove theatmospheric air between the container and the door and fill in thenitrogen gas (purge), while the container is attached to the openingportion. Therefore, atmospheric air between the container and the door,which contains oxygen, moisture, particles and the like that may cause achange in the characteristics of the wafer such as oxidation of thewafer is prevented from entering the conveyance space or the containerwhen the door is opened. In other words, oxygen, moisture, and particlesin the sealed space can be eliminated before opening the sealed space byopening the lid member of the container. As a result, oxygen and thelike do not leak into the container or the conveyance space when the lidmember is opened, which makes it possible to maintain the cleanliness ofthe inside of the container and the conveying space.

The load port related to the present invention includes:

-   -   a second seal member for sealing between the base and the door;    -   a sealed space defined by the base, the first seal member, the        second seal member, the lid member, and the door while the        container is in contact with the base, and while the door abuts        the base via the second seal member, wherein    -   when the container is clamped to the base, the container is        moved towards the door from a state in which the door and the        lid member are separate from each other.

In this load port, when the container is clamped to the base, thecontainer is moved towards the door from a state in which the door andthe lid member are separate from each other. This way, the sealingperformance between the container and the base through the first sealmember is improved.

Advantageous Effects of Invention

With the present invention, even if the lid member of the container isinflated towards the base, the container-side end surface of the door ispositioned closer to the conveyance space than the container-side endportion of the first seal member, when the container is attached to theopening portion. Therefore, the lid member and the door do not contacteach other. This prevents the lid member from contacting the door andscattering fragments, and keeps the space surrounding the load portclean. Further, it is possible to restrain an impact of contact fromstirring up the dusts on the door, or from shaking the container to stirup the dusts at the bottom portion of the container or deviate theposition of accommodated article from the proper position.

In the present invention, the container-side end surface of the door isat least partially positioned closer to the conveyance space than thecontainer-side end portion of the first seal member which is clamped andpressed against the base. Therefore, it is possible to reliably preventcontact of the lid member with the door, while the container is attachedto the opening portion.

With the present invention, it is possible to reliably prevent the lidmember from contacting the door, even if the lid member of the containeris inflated towards the base.

In the present invention, the shape of the recess corresponds to theinflated surface of the lid member which is inflated by increasing thepressure inside the container. Therefore, the lid member and the doorare reliably kept from contacting each other, even if the containerinflates in various shapes.

In the present invention, a container-side end surface of the door isentirely positioned closer to the conveyance space than a container-sideend portion of the first seal member. Thus, while the lid member and thedoor are reliably kept from contacting each other, sealing by the secondseal member between the base and the door unit is maintained.

The present invention includes: the first gas injection unit configuredto inject gas into the sealed space formed between the container and thedoor, while the container is in contact with the opening portion via thefirst seal member, i.e., while the container is attached to the openingportion, and the first gas discharge unit configured to discharge gasfrom the sealed space. With this, it is possible to remove theatmospheric air between the container and the door and fill in thenitrogen gas (purge), while the container is attached to the openingportion. Therefore, atmospheric air between the container and the door,which contains oxygen, moisture, particles and the like that may cause achange in the characteristics of the wafer such as oxidation of thewafer is prevented from entering the conveyance space or the containerwhen the door is opened. In other words, oxygen, moisture, and particlesin the sealed space can be eliminated before opening the sealed space byopening the lid member of the container. As a result, oxygen and thelike do not leak into the container or the conveyance space when the lidmember is opened, which makes it possible to maintain the cleanliness ofthe inside of the container and the conveying space.

In the present invention, when the container is clamped to the base, thecontainer is moved towards the door from a state in which the door andthe lid member are separate from each other. This way, the sealingperformance between the container and the base through the first sealmember is improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A plan view schematically showing a relation between an EFEM anda processing apparatus related to an embodiment of the presentinvention.

FIG. 2 A side view showing a state in which a side wall of the EFEM isdetached.

FIG. 3 A perspective view showing a part of the EFEM broken away.

FIG. 4 A schematic diagram showing a flow of the gas in a circulationpath of EFEM.

FIG. 5 A perspective view of the load port of FIG. 1.

FIG. 6 A front view of the load port of FIG. 1.

FIG. 7 A rear view of the load port of FIG. 1.

FIG. 8 A side cross sectional view of the load port of FIG. 1.

FIG. 9 A partially enlarged cross sectional view showing a relationshipbetween a door unit and a first seal member.

FIG. 10 A side cross sectional view showing a state where the FOUP ismoved from the state shown in FIG. 8, towards the casing.

FIG. 11 A partially enlarged cross sectional view showing the sealedspace portion sealed by the sealing member.

FIG. 12 A partially enlarged cross sectional view showing a state wherethe FOUP is brought close to the door unit by clamping.

FIG. 13 A side cross sectional view showing a state where the door unitalong with the lid member of the FOUP are moved away from the openingportion as compared with the state shown in FIG. 10.

FIG. 14 A side cross sectional view showing a state where the door unitalong with the lid member of the FOUP are moved downward from the stateshown in FIG. 13.

FIG. 15 An enlarged perspective view providing an enlarged view of themain parts of a window unit and the door unit constituting the EFEM.

FIG. 16 An enlarged cross sectional view providing an enlarged view ofthe main part of a cross section taken along A-A shown in FIG. 15.

FIG. 17 An enlarged front view of a main part showing a clamp providedin a window unit.

FIG. 18 A block diagram showing a connection state amongst a controllingunit, pressure gauges, valves.

FIG. 19 A flowchart showing a procedure of connecting and communicatingthe FOUP with EFEM.

FIG. 20A is a cross sectional view showing a modification of the clampunit, and FIG. 20B is a front view showing the clamped state of FIG.20A.

FIG. 21A is a cross sectional view showing state where the clamp unit ofFIG. 20 is released, and FIG. 21B is an enlarged cross sectional viewshowing a support piece shown in FIG. 21A.

FIG. 22A is an enlarged plan view showing a state where the clamp unitis released, FIG. 22B is an enlarged plan view showing a state where theclamp unit is in operation, and FIG. 22C is an enlarged plan viewshowing a clamped state.

FIG. 23A is a cross sectional view showing a door unit of a modificationhaving a recessed portion depressed toward a conveyance space, and FIG.23B is a cross sectional view showing a door unit of the modificationhaving a curved surface formed in a shape bowed towards the side of theconveying space.

FIG. 24A is a cross sectional view showing a door unit of anothermodification having a recessed portion depressed toward a conveyancespace, and FIG. 24B is a cross sectional view showing a door unit of theother modification having a curved surface formed in a shape bowedtowards the side of the conveying space.

FIG. 25 A view showing a gas passage related to a modification, wherethe pressure P1 is higher than P2.

FIG. 26 A view showing a gas passage related to a modification, wherethe pressure P1 is lower than P2.

FIG. 27 A block diagram showing a modification of a connection stateamongst a controlling unit, pressure gauges, valves.

FIG. 28 A partially enlarged cross sectional view showing a modificationin which the door unit is advanced towards the lid member of the FOUP,from the state of FIG. 11.

FIG. 29 A cross-sectional view showing a modification in which twoO-rings are integrated.

DESCRIPTION OF EMBODIMENTS

The following describes an embodiment of the present invention withreference to attached drawings.

FIG. 1 is a plan view schematically showing a relation between an EFEM1and a processing apparatus 6 connecting thereto, related to anembodiment of the present invention. A top plate and the like of EFEM1and the processing apparatus 6 are removed so as to show their inside.Further, FIG. 2 is a side view showing the inside of the EFEM1 byremoving its side face wall. As shown in FIG. 1 and FIG. 2, the EFEM 1includes: a wafer conveyance apparatus 2 configured to convey a wafer Wbetween predetermined delivery positions; a box-shape casing 3 providedto surround the wafer conveyance apparatus 2; a plurality of (three inthe figure) load ports 4 connected to the outside of a wall on the frontsurface side (front wall 31) of the housing 3; and a controller 5.

In the present application, when seen from the casing 3, a direction tothe side to which the load ports 4 are connected is defined asfrontward, and a direction to the side of the rear wall 32, which isopposite to the front wall 31, is defined as rearward. Further, adirection perpendicular to the vertical direction and the front-reardirection are defined as side. In other words, the three load ports 4are aligned on a side.

Further, as shown in FIG. 1, EFEM 1 is configured so that a load lockchamber 61 constituting a part of the processing apparatus 6 isconnectable adjacent to the outside of the rear wall 32. By opening adoor 1 a provided between the EFEM 1 and the load lock chamber 61, theload lock chamber 61 is in communication with the inside of the EFEM 1.The processing apparatus 6 may be any of a wide variety of apparatuses.In general, the conveyance chamber 62 is provided adjacent to the loadlock chamber 61, and a plurality of (three in the figure) processingunits 63 each configured to perform processing to wafers W are providedadjacent to the conveyance chamber 62. Between the conveyance chamber 62and the load lock chamber 61 or each of the processing units 63, a door62 a or a door 63 a is provided which brings these components incommunication with each other when opened. In addition, the wafer W ismovable between the load lock chamber 61 and the processing units 63 byusing a conveyance robot 64 provided in the conveyance chamber 62.

As shown in FIG. 2, the wafer conveyance apparatus 2 includes an armunit 2 a having a pick for conveying a wafer W placed thereon, and abase unit 2 b supporting the arm unit 2 a from below, and having adriving mechanism and an elevation mechanism for operating the arm unit.The base unit 2 b is supported on the front wall 31 of the casing 3through a support 21 and a guide rail 22. The wafer conveyance apparatus2 is able to move along the guide rail 22 which extends in a widthdirection of the casing 3. By the controller 5 controlling an operationof the wafer conveyance apparatus 2, it is possible to convey a wafer(accommodated article) W in the FOUP (container) 7 of any of the loadports 4 aligned on a side to a load lock chamber 61, and convey thewafer W back to the FOUP 7 after it is subjected to processing in theprocessing unit 63.

The casing 3 is structured by the front wall 31, the rear wall 32, andside walls 33 and 34 which surround the four sides of the waferconveyance apparatus 2; a ceiling 35, a bottom 36, and pillars 37 a to37 d supporting the walls 31 to 35 of the casing. To an opening portion92 formed in the front wall 31, a load port 4 is attached. To arectangular opening 32 a provided in the rear wall 32, the load lockchamber 61 is connected. The casing 3 has a conveyance space 9 and alater-described gas return path 10, and a substantially closed space CS(see FIG. 4) including these is formed. It should be noted that theabove-mentioned members are precisely assembled so as not to create aspace from which internal gas do not leak out to the interface betweenthe members; however, it is possible to provide a sealing member betweenthe members to achieve an air-tight structure of the casing 3. Further,an opening 32 a provided in the rear wall 32 has a driving mechanism 1b, and is closable by a door 1 a (see FIG. 3) generally referred to as agate valve, which is driven in vertical directions. Althoughillustration and description are omitted, the side walls 33, 34 are alsoprovided with openings, one of which is connected to an aligner used forposition adjustment of a wafer W, and the other one of which is anopening for maintenance which is usually closed.

The load ports 4 each includes a door unit 81, and with the movement ofthe door unit 81 along with the lid member 72 provided to the FOUP 7,the FOUP 7 is opened with respect to the substantially closed space CS.The FOUP 7 is provided with many carrier units in the up-down directionsso as to enable accommodation of many wafers W. Further, nitrogen isusually filled in the FOUP 7, and it is also possible to replace theatmosphere in the FOUP 7 with nitrogen, through load port 4, undercontrol of the controller 5.

The controller 5 is structured as a controller unit provided in an upperspace US above the ceiling 35, between the ceiling 35 and a top plate 38of the casing 3. Further, the controller 5 performs drive control of thewafer conveyance apparatus 2, nitrogen substitution control of the FOUP7 by the load port 4, opening/closing control of the door 1 a and thedoor unit 81, nitrogen circulation control in the casing 3, and thelike. The controller 5 is constituted by an ordinary microprocessor andthe like having a CPU, a memory, an interface, and the like. The memorystores therein in advance programs necessary for processing, and the CPUsuccessively retrieves and runs necessary programs, to achieve adesirable function in cooperation with peripheral hard resources. Thenitrogen circulation control is described later.

As shown in FIG. 4, the substantially closed space CS is partitioned bya partition member 8, into the conveyance space 9 in which the waferconveyance apparatus 2 is driven, and a gas return path 10. Theconveyance space 9 and the gas return path 10 are in communication witheach other only through a gas delivery port 11 provided in the widthdirection, in the upper portion of the conveyance space 9 and a gassuction port 12 provided in the width direction, in the lower portion ofthe conveyance space 9. The gas delivery port 11 and the gas suctionport 12 generates a downward air current in the conveyance space 9, andgenerates a rising air current in the gas return path 10 to form acirculation path Ci indicated by arrows in FIG. 4 in the substantiallyclosed space CS, thereby circulating gas. The present embodiment dealswith a case where nitrogen which is an inert gas is circulated in thesubstantially closed space CS; however, the gas to be circulated is notlimited to nitrogen, and may be other gases.

Next, the following details the structure of the gas return path 10. Asshown in FIG. 4, the gas return path 10 is a space closed by the bottom36, the rear wall 32, the ceiling 35, and the partition member 8.Further, the gas return path 10 is provided for returning gas sucked infrom the gas suction port 12 in the lower portion of the conveyancespace 9 to the gas delivery port 11 in the upper portion of theconveyance space 9.

To the rear side of the upper portion of the return path 10, a gassupplier (third gas injection unit) 16 for supplying nitrogen into thesubstantially closed space CS is connected. The gas supplier 16 iscapable of controlling supply of the nitrogen and stop supplying ofnitrogen based on a command from the controller 5. Therefore, when partof nitrogen leaks outside the substantially closed space CS, the gassupplier 16 supplies an amount of nitrogen having leaked out, tomaintain constant nitrogen atmosphere in the substantially closed spaceCS. To the rear side of the lower portion of the return path 10, a gasdischarger (third gas discharge unit) 17 for discharging gas in thesubstantially closed space CS is connected. The gas discharger 17operates based on commands from the controller 5, and opens a not-shownshutter to communicate the inside of the substantially closed space CSwith a gas delivery destination provided outside. With combination ofthe nitrogen supply by the above-mentioned gas supplier 16, substitutionof nitrogen atmosphere in the substantially closed space CS is possible.It should be noted that the present embodiment deals with a case wherethe gas supplier 16 supplies nitrogen, because the gas circulated in thecirculation path Ci is nitrogen; however, in cases where a different gasis circulated, the gas supplier 16 circulates that gas circulated.

Further, the gas delivery port 11 is provided with a fan filter unit 13(FFU 13) which is constituted by a fan 13 a serving as a firstwind-blower and a filter 13 b. The fan filter unit 13 removes particlescontained in the gas circulated in the substantially closed space CS,and blows wind downward in the conveyance space 9, thereby generatingthe downward air current within the conveyance space 9. It should benoted that the FFU 13 is supported by a support member 18 extendedhorizontally and connected to the partition member 8.

On the other hand, the gas suction port 12 is connected to a chemicalfilter 14, and the gas in the conveyance space 9 flows into the gasreturn path 10 through the chemical filter 14. As mentioned hereinabove,the wafer conveyance apparatus 2 (see FIG. 2) is supported on the frontwall 31 of the casing 3 through the support 21 and the guide rail 22.Therefore, the gas suction port 12 is largely opened upward withoutinterfering with the wafer conveyance apparatus 2. Further, as describedabove, since the gas suction port 12 extends in the width direction, itis possible to effectively suck particles even when particles aregenerated at a time of driving the wafer conveyance apparatus 2 alongthe guide rail 22 which is also extended in the width direction. Withprovision of the chemical filter 14 to the gas suction port 12, it ispossible to remove molecules of contaminant generated in the processingapparatus 6 (see FIG. 1) and having flown into the conveyance space 9.Further, on the rear side of the chemical filter 14 in the gas returnpath 10, a fan 15 as a second wind-blower is provided across the widthdirection (see FIG. 4). The fan 15 blows air toward the downstream sideof the gas return path 10, i.e., towards up in FIG. 4, therebygenerating a gas suction force at the gas suction port 12, and deliversthe gas having passed through the chemical filter 14 to move upwardthereby generating a rising air current in the gas return path 10.

Thus, with the above-described fan 13 a of FFU 13 and the fan 15, thegas in the substantially closed space CS is circulated by flowingdownward in the conveyance space 9, and then flowing upward in the gasreturn path 10. Since the gas delivery port 11 is opened downward, gasis sent downward by the FFU 13. Since the gas suction port 12 is openedupward, the gas is sucked downward as it is without disturbing thedownward air current generated by the FFU 13, thereby creating a smoothflow of the gas. The downward air current in the conveyance space 9removes particles on wafers W are removed, and prevent the particlesfrom floating in the conveyance space 9.

Next, the following describes, with reference to FIG. 4, an operation ofnitrogen circulation control for circulating nitrogen in the EFEM 1structured as described above.

First, as the initial stage, the controller 5 causes the gas supplier 16to supply nitrogen to the substantially closed space CS while causingthe gas discharger 17 to discharge gas. This way, the atmosphere of thesubstantially closed space CS of the EFEM 1 is purged, and substitutedwith a nitrogen atmosphere. After this state, if nitrogen in thecirculation path Ci leaks outside, the controller 5 causes the gassupplier 16 to supply nitrogen according to the amount of nitrogenleaked out.

Then, by the controller 5 driving the fan 13 a of the FFU 13 and the fan15 in the substantially closed space CS with the nitrogen atmosphere,circulation of the gas through the circulation path Ci is created. Atthis time, in order to remove particles and molecules of contaminant inthe gas circulating through the filter 13 b of the FFU 13 and thechemical filter 14, a downward air current of clean nitrogen isconstantly generated in the conveyance space 9.

In the EFEM 1 in the above state, wafers W are conveyed by communicatingthe FOUP 7 which is placed in the load port 4 and which has a nitrogenatmosphere with the conveyance space 9. At this time, both theconveyance space 9 and the FOUP 7 are in the same nitrogen atmosphere,and the nitrogen in the conveyance space 9 is also kept clean.Therefore, the pressure inside the FOUP 7 does not have to be madepositive with respect to the pressure in the conveyance space 9 for thepurpose of preventing particles and molecules of contaminant fromentering the FOUP 7, and the consumption amount of nitrogen to besupplied to the FOUP 7 is restrained.

FIG. 5, FIG. 6, and FIG. 7 are a perspective view, a front view, and arear view of the load port 4, respectively. With reference to thesefigures, the structure of the load port 4 is described. It should benoted that, in these figures, an outside cover 42 (see FIG. 3) locatedin a lower part of the placement table 44 is removed to partially exposethe internal structure.

In the load port 4, a base 41 extends upright from the rear of a bottomportion 45 to which casters and installation legs are attached, and ahorizontal base portion 43 extends forward from a height position ofapproximately 60% of the base 41. Further, the placing table 44 forplacing the FOUP 7 (see FIG. 2) is provided on the horizontal baseportion 43.

As schematically shown in FIG. 8, the FOUP 7 includes: a main body 71having an internal space Sf for accommodating therein wafers W (see FIG.2); and a lid member 72 which opens and closes an opening 71 a which isprovided on one side of the main body 71 to serve as an entrance forwafers W. When the FOUP 7 is correctly placed on the placement table 44,the lid member 72 faces the base 41. A space Sc is formed inside the lidmember 72 so as to accommodate therein a later-described connecting unit82 (see FIG. 7) for opening and closing the lid member 72 (see FIG. 11).

As shown in FIG. 5 and FOUP7, the placement table 44 is provided with apositioning pin 44 a for positioning the FOUP 7, and a lock protrusion44 b for fixing the FOUP 7 to the placement table 44. Through a lockingoperation, the lock protrusion 44 b, in cooperation with the positioningpin 44 a, is able to guide and fix the FOUP 7 to a proper position.Through an unlocking operation, the FOUP 7 is separable from theplacement table 44. It should be noted that the placement table 44 ismoveable in the front-rear directions by a placement table driving unit(not shown), while having the FOUP 7 placed thereon.

Further, the placement table 44 includes two second gas injectionnozzles (second gas injection units) 44 c each configured to supply gasinto the FOUP 7 and two second gas discharge nozzles (second gasdischarge units) 44 d each configured to discharge gas from the insideof the FOUP 7. Each of the second gas injection nozzles 44 c and each ofthe second gas discharge nozzles 44 d are usually positioned lower thanthe top surface of the placement table 44, and advances upward toconnect with a gas supply valve 73 and a gas discharge valve 74 (seeFIG. 8) of the FOUP 7, respectively, at a time of use.

At a time of use, one end of the second gas injection nozzle 44 ccommunicates with the inside of the FOUP 7, and the other end thereof isprovided with a second gas injection valve 44 e. Similarly, one end ofthe second gas discharge nozzle 44 d communicates with the inside of theFOUP 7, and the other end thereof is provided with a second gasdischarge valve 44 f. Through the gas supply valve 73, gas, such as drynitrogen gas and the like is supplied to the internal space Sf of theFOUP 7 from the second gas injection nozzle 44 c, and the gas in theinternal space Sf is discharged from the second gas discharge nozzle 44d through the gas discharge valve 74, thereby enabling gas-purge. Bymaking a gas-supply amount larger than a gas-discharge amount, thepressure of the internal space Sf is set positive with respect to thepressure of the internal space Se of the casing 3 (see FIG. 2) or theoutside. By raising the pressure in the FOUP 7 (internal space Sf), thesurface of the lid member 72 is inflated towards the door unit 81 thanan abutting surface 71 b, as shown in FIG. 11.

The base 41 constituting the load port 4 constitutes a part of the frontwall 31 which separates the conveyance space 9 from the external space.As shown in FIG. 5, the base 41 includes: pillars 41 a provided uprighton both sides, a base main body 41 b supported by the pillars 41 a, anda window unit 90 attached to a substantially rectangular window part 41c formed on the base main body 41 b. The substantially rectangular shapeherein means a basically rectangular shape with four sides, such thatthe four corners thereof are each formed in a smooth arc. In thevicinity of the outer circumference of the rear surface of the base mainbody 41 b, a gasket 47 (see FIG. 7) serving as an elastic member formedin a rectangular shape is provided. The gasket 47 is formed of a rubbermaterial with less gas permeation.

The window unit 90 is provided in a position to face the lid member 72(see FIG. 8) of the FOUP 7 described above. The window unit 90 isprovided with the rectangular opening portion 92 (see FIG. 15) ashereinbelow detailed, and hence is capable of opening the internal spaceSe of the casing 3 through this opening portion 92. The load port 4 hasan opening/closing mechanism 80 which opens and closes the window unit90 configured to be attachable to the FOUP 7.

As shown in FIG. 6, the opening/closing mechanism 80 includes: the doorunit 81 configured to open and close the opening portion 92; a supportframe 83 for supporting the door unit 81; a movable block 85 thatsupports the support frame 83 movably in the front-rear directions via aslide supporter 84; and a sliding rail 86 that supports the movableblock 85 movably with respect to the base main body 41 b in the verticaldirections.

As shown in FIG. 8, the support frame 83 supports the lower rear portionof the door unit 81, and has a substantially clamp shape which extendsdownwards, and then protruding forward from the base main body 41 b,passing through a slit-shaped insertion hole 41 d provided to the basemain body 41 b. The slide supporter 84 that supports the support frame83, the movable block 85, and the sliding rail 86 are provided in frontof the base main body 41 b. Thus, driving parts for moving the door unit81 are on the outer side of the casing 3, and even if particles aregenerated in these parts, the particles are restrained from entering thecasing 3 because the insertion hole 41 d is formed in a smallslit-shape.

The following details the door unit 81 of the opening/closing mechanism80. As shown in FIG. 8, the door unit 81 is provided with a first gasinjection nozzle (first gas injection unit) 87 configured to inject gasbetween the FOUP 7 and the door unit 81, and a first gas dischargenozzle (first gas discharge unit) 88 configured to discharge gas betweenthe FOUP 7 and the door unit 81, when the FOUP 7 is attached to thewindow unit 90. One end of the first gas injection nozzle 87 extends tothe outer surface of the door unit 81, and the other end portion isprovided with a first gas injection valve 87 a. Similarly, one end ofthe first gas discharge nozzle 88 extends to the outer surface of thedoor unit 81, and the other end portion is provided with a first gasdischarge valve 88 a. While the door unit 81 and the lid member 72 areintegrated through a clamp-operation as hereinafter described, the firstgas injection nozzle 87 which is in communication with the sealed spaceSd (see FIG. 11) supplies thereto a gas such as dry nitrogen gas and thelike, and the first gas discharge nozzle 88 which is in communicationwith the sealed space Sd discharges therefrom the gas, thereby enablinggas-purge. It should be noted that the first gas discharge nozzle 88 isbranched off to the equalizing valve 89, and is used as a nozzle forpressure equalization which equalizes the pressures of the sealed spaceSd and the conveyance space 9.

FIG. 9 is a partially enlarged cross sectional view of FIG. 8 showing arelationship between the door unit 81 and an O-ring (first seal member)94. As shown in FIG. 9, an FOUP 7-side end surface 81 c of the door unit81 is shifted towards the conveyance space 9 by a desirable dimension ofL2 from an FOUP 7-side end portion of the O-ring 94. Therefore, the FOUP7-side end surface 81 c of the door unit 81 is entirely positionedcloser to the conveyance space 9 than the FOUP 7-side end portion of theO-ring 94. Thus, while the lid member 72 and the door unit 81 arereliably kept from contacting each other, sealing by the O-ring 96between the base 41 and the door unit 81 is maintained. It should benoted that the figure indicates with an imaginary line L1 the positionof the FOUP 7-side end portion of the O-ring 94. The dimension L2 is,for example, 0.1 mm or more but not more than 3 mm.

Further, actuators (not shown) are provided for moving the door unit 81in the front-rear directions and the up-down directions, and the doorunit 81 is movable in the front-rear directions and in the up-downdirections, with drive instructions to these actuators, from thecontrolling unit Cp.

Further, in front of the base main body 41 b, there is a cover 46 (seeFIG. 8) which extends downward from immediately below the horizontalbase portion 43, and the support frame 83, the slide supporter 84, themovable block 85, and the sliding rail 86 are covered and sealed by thecover 46. Therefore, although the insertion hole 41 d is formed in thebase main body 41 b, the gas in the housing 3 (see FIG. 3) does not flowoutside through this insertion portion. Inside the cover 46 are thelower end of the first gas injection nozzle 87, the first gas injectionvalve 87 a, the first gas discharge nozzle 88, and the first gasdischarge valve 88 a.

The door unit 81 includes: an adsorption unit 79 (see FIG. 6) configuredto adsorb the lid member 72 of the FOUP 7 and a connecting unit 82 (seeFIG. 7) for performing a latch operation to open and close the lidmember 72 of the FOUP 7, and for holding the lid member 72. The doorunit 81 fixes or release the fix of the lid member 72 so as to enableremoval and attachment of the lid member 72 from/to the FOUP 7. Theconnecting unit 82 makes the lid member 72 an openable state through anunlatching operation of the lid member 72, and integrate by coupling thelid member 72 to the door unit 81. To the contrary, the connecting unit82 is capable of releasing the lid member 72 from the door unit 81, andattach the lid member 72 to the main body 71.

Here, with reference to FIG. 15, the following describes details of thestructure of the above-mentioned window unit 90. The window unit 90includes a window frame 91, O-rings 94 and 96 serving as elastic membersto be attached thereto, and clamp units 50 each serving as an attractingunit which brings the FOUP 7 into close contact with the window frame 91via the O-ring 94.

The window frame 91 has a frame-shape with a substantially rectangularopening portion 92. The window frame 91 constitutes a part of the base41 (see FIG. 5) described above as a constituting element of the windowunit 90, the opening portion 92 opens the front wall 31 serving as awall surface of the casing 3. On the front surface of the window frameportion 91, the O-ring 94 is disposed so as to circle around thevicinity of the rim of the opening portion 92. On the rear surface ofthe window frame portion 91, the O-ring 96 is disposed so as to circlearound the vicinity of the rim of the opening portion 92.

The opening portion 92 is slightly larger than the outer circumferenceof the lid member 72 (see FIG. 8) of the FOUP 7, and the lid member 72is moveable through this opening portion 92. Further, during a statewhere the FOUP 7 is placed on the placement table 44, the front surfaceof the main body 71, as an abutting surface 71 b, which surrounds thelid member 72 abuts the front surface of the window frame 91 via theO-ring 94. This way, the O-ring 94 seals off the rim of the openingportion 92 (base 41) and the FOUP 7 (see FIG. 16), while the FOUP 7 isattached to the window unit 90.

Further, on the rear surface of the window frame 91, the door unit 81described above is abutted through the O-ring (second seal member) 96.This way, the O-ring 96 seals off the rim of the opening portion 92 andthe door unit 81. Specifically, a thin portion 81 a provided in aflange-like manner abuts against the outer circumference of the doorunit 81. Since a thick portion 81 b on the inner side of the thinportion 81 a is formed smaller than the opening portion 92, it protrudesforward through the opening portion 92.

As shown in FIG. 15, the clamp units 50 are arranged in four positionsin total, on both sides of the window frame 91, apart from each other inthe up-down directions. Each clamp unit 50 is generally constituted byan engagement piece 51 and a cylinder 52 which operates the engagementpiece 51, and presses the FOUP 7 against the base 41, while the FOUP 7is attached to the window unit 90.

The cylinder 52 constituting the clamp unit 50 is attached on the rearside of the window frame 91, and has a shaft 53 which is capable tomoving forward and retracting through a hole provided in the windowframe 91. To the leading end of the shaft 53 is attached the base end 51a of the engagement piece 51, and the leading end 51 b extends from thisbase end 51 a towards the outer circumferential direction of the shaft53. On the outer circumference of the shaft 53, a guide groove 53 awhose phase is twisted by 90° in the axial direction is formed. Insidethe guide groove 53 a, a guide pin 54 fixed to the side of the windowframe 91 is inserted from a radial direction. Therefore, with movementof the cylinder 52 forward or backward, the guide groove 53 a is guidedby the guide pin 54, and the shaft 53 pivots 90° around the axialcenter.

Then, as shown in FIG. 17, when the engagement piece 51 sticks outforward along with the shaft 53, the leading end 51 b faces upward, andwhen the engaging piece 51 is drawn rearward, the leading end 51 b isdirected towards the inside of the FOUP 7. With the leading end 51 b ofthe engagement piece 51 directed inside through the clamp operation, itengages with the flange portion 71 c sticking out from the FOUP 7towards a side. While maintaining this engaged state, the shaft 53 isfurther retracted by the cylinder 52. This way, the abutting surface 71b of the FOUP 7 is brought into a clamped state of further tightlyattached to the O-ring 94. Such a clamp unit 50, when operated in fourpositions, evenly deforms the O-ring 94 and improves the sealingperformance. During the clamped state too, the FOUP 7-side end surface81 c of the door unit 81 is positioned closer to the conveyance space 9than the FOUP 7-side end portion of the O-ring 94, which is pressedtowards the side of the base 41 by the abutting surface 71 b of the FOUP7.

Further, when the engagement piece 51 is moved forward, the leading end51 b is directed upward so as not to interfere with the flange portion71 c, when viewed from the front. This way, the FOUP 7 is movable withthe placement table 44. It should be noted that, to move the leading end51 b forward, the leading end 51 b may be directed not only the upwarddirection, but also a downward or an outward direction, as long as theleading end 51 b does not interfere with the flange portion 71 c.

The load port 4 structured as described above is given driveinstructions for various parts thereof to operate, from the controllingunit Cp shown in FIG. 5. Further, as shown in FIG. 18, an input end ofthe controlling unit Ct is connected to a pressure gauge for measuringthe pressure of the sealed space Sd, a pressure gauge for measuring thepressure of the internal space Sf of the FOUP 7, and a pressure gaugefor measuring the pressure of the internal space Se of the casing 3.Similarly, an input end of the controlling unit Ct is connected to ahygrometer for measuring the humidity of the sealed space Sd, ahygrometer for measuring the humidity of the internal space Sf of theFOUP 7, and a hygrometer for measuring the humidity of the internalspace Se of the casing 3. An input end of the controlling unit Ct formeasuring the oxygen concentration is connected to an oxygen(concentration) gauge for measuring the oxygen concentration of thesealed space Sd, an oxygen (concentration) gauge for measuring theoxygen concentration of the internal space Sf of the FOUP 7, and anoxygen (concentration) gauge for measuring the oxygen concentration ofthe internal space Se of the casing 3. An input end of the controllingunit Ct related to the flow rate is connected to a flowmeter formeasuring the flow rate of the first gas injection nozzle 87, aflowmeter for measuring the flow rate of the second gas injection nozzle44 c, and a flowmeter for measuring the flow rate of the third gasinjection unit 16.

An output end of the controlling unit Ct is connected to the first gasinjection valve 87 a, the first gas discharge valve 88 a, the second gasinjection valve 44 e, the second gas discharge valve 44 f, a third gasinjection valve, a third gas discharge valve, the gas supplier 16, thegas discharger 17 and the equalizing valve 89, via a flow ratecontroller Cf, and is connected to the clamp units 50, the connectingunit 82, and the adsorption unit 79, via a drive controller Cd. Thecontrolling unit Ct is installed in the EFEM 1 and includes variousmemories and controllers for accepting operation by a user. Amongstthese controllers of the EFEM1 are the flow rate controller Cf and thedrive controller Cd.

The following describes, with reference to FIG. 8 to FIG. 12, an exampleoperation involving the load ports 4 of the present embodiment. In theinitial state, each valve is closed.

FIG. 8 shows a state in which the FOUP 7 is placed on the placementtable 44, and spaced from the base 41. During this state, the door unit81 abuts the rear surface of the window frame 91 (see FIG. 15)constituting the window unit 90, via the O-ring 96. Therefore, therewill be no space between the window frame 91 and the door unit 81, and ahigh sealing performance is achieved. This restrains leakage of gas tothe outside when the internal space Se of the casing 3 is filled withnitrogen gas and the like, and restrains an outside gas from enteringinto the internal space Se.

As shown in FIG. 19, in step S1, the FOUP 7 is suitably positioned andfixed to the placement table 44 by locking operation by the lockprotrusion 44 b (see FIG. 5) and positioning action done by thepositioning pins 44 a.

Then, the second gas injection nozzle 44 c and the second gas dischargenozzle 44 d of the placement table 44 protrude upward and connect to thegas supply valve 73 and the gas discharge valve 74 of the FOUP 7. In thefollowing step S2, the second gas injection valve 44 e is opened tosupply fresh and dry nitrogen gas through the second gas injectionnozzle 44 c and the gas supply valve 73. By opening the second gasdischarge nozzle 44 f at the same time, the gas having been accumulatedin the internal space Sf is discharged through the gas discharge valve74 and the second gas discharge nozzle 44 d. Through this gas-purgeoperation, the internal space Sf is filled with the nitrogen gas whilethe pressure is made higher than the pressure of the internal space Seof the casing 3. It should be noted that, the filling in of the nitrogengas to the FOUP 7 is continued until the present flow ends.

Next, in step S3, the placement table 44 is moved rearward to have theabutting surface 71 b of the FOUP 7 abut the window frame 91, as shownin FIG. 10. At this time, the end surface 81 c of the door unit 81 ispositioned closer to the conveyance space 9 than the FOUP 7-side endportion of the O-ring 94, by a predetermined dimension of L2. Therefore,even if the lid member 72 of the FOUP 7 is inflated towards the doorunit 81, the lid member 72 does not contact the end surface 81 c of thedoor unit 81, because the abutting surface 71 b of the FOUP 7 abuts theO-ring 94 when the FOUP 7 is brought closer to the window unit 90 (secFIG. 11). Therefore, scaling between the O-ring 96 and the door unit 81is reliably maintained. As described, the abutting surface 71 b abutsthe window frame 91 via the O-ring 94, and the door unit 81 abuts thewindow frame 91 via the O-ring 96, thereby forming the sealed space Sd.The base 41, the O-rings 94 and 96, the lid member 72, and the door unit81 which form the sealed space Sd, along with the opening portion 92,the first gas injection nozzle 87 and the first gas discharge nozzle 88constitute the door operation system.

To move the placement table 44, the engagement pieces 51 (see FIG. 15)are protruded forward in advance by the cylinders 52 constituting theclamp units 50, so that their the leading ends 51 b are directed upwardand do not interfere with the FOUP 7.

Then, in step S4, the FOUP 7 is clamped and fixed to the window unit 90.Thus, from the state in which the door unit 81 and the lid member 72 areapart from each other, bringing the FOUP 7 closer to the door unit 81causes elastic deformation of the O-ring 94, thus improving the sealingperformance between the FOUP 7 and the base 41 (see FIG. 12). It ispreferable to set the distance between the door unit 81 and the lidmember 72, when the FOUP 7 is brought closer to the door unit 81 by theclamp units 50, to a distance that enables the above-described latchingoperation and unlatching operation.

Specifically, the engagement pieces 51 are retracted rearward by thecylinders 52 constituting the clamp units 50, so as to engage with theflange portion 71 c of the FOUP 7 with the leading ends 51 b directedinward. Further retracting the leading ends 51 b causes the abuttingsurface 71 b of the FOUP 7 further firmly contact the O-ring 94, thusimproving the sealing performance. The series of the above operations isreferred to as the clamp operation. At this time, as shown in FIG. 11, aspace Sg is formed between the lid member 72 and the door unit 81, whichis in communication with the internal space Sc of the lid member througha fitting hole 75 to which the connecting unit 82 is fitted. The spaceSg and the space Sc constitutes the sealed space Sd between the FOUP 7and the door unit 81.

In step S5, the connecting unit 82 (see FIG. 7) provided to the doorunit 81 is operated to make the lid member 72 in the unlatched state anddetachable from the main body 71, while the door unit 81 integrallyholds the lid member 72 through the adsorption unit 79.

In step S6, the first gas injection valve 87 a is opened to supplynitrogen gas to the sealed space Sd from the first gas injection nozzle87. At the same time, the first gas discharge valve 88 a is opened todischarge the gas (atmospheric air) having been accumulated in thesealed space Sd from the first gas discharge nozzle 88. After elapse ofa predetermined time, the first gas injection valve 87 a and the firstgas discharge valve 88 a are closed to end filling of the gas to thesealed space Sd. It should be noted that the gas injection operation ofinjecting gas into the sealed space Sd by the first gas injection nozzle87 and the discharge operation of discharging gas from the sealed spaceSd by the first gas discharge nozzle 88 may be repeated. The atmosphericair herein encompasses oxygen, moisture, particles, and the like whichmay cause a change in the properties of the wafers W, such as oxidationof the wafers W. Further, discharging of the gas (atmospheric air)having accumulated in the sealed space Sd means not only discharging ofthe atmospheric air present between the FOUP 7 and the door unit 81, butalso means discharging the gas inside the lid member 72, to enablefilling of the gas is possible.

In step S7, the pressures of the internal space Sf of the FOUP 7 and thesealed space Sd are equalized. Specifically, where the pressure insidethe internal space Sf after the clamp operation is P1 and the pressureof the sealed space Sd is P2, the P1 and P2 are controlled toapproximate each other.

This pressure adjustment is done by adjusting the flow rates of thefirst gas injection nozzle 87 and the first gas discharge nozzle 88,based on the pressures detected by the pressure gauges of the sealedspace Sd and the FOUP 7. However, pressure adjustment may be performedwithout using a pressure gauge. Specifically, a pressure is estimatedbased on the flow rates of the first gas injection nozzle 87 and thefirst gas discharge nozzle 88, and the flow rates of the second gasinjection nozzle 44 c and the second gas discharge nozzle 44 d, and thepressure adjustment may be performed based on this estimated pressure.This contributes to cost reduction because pressure adjustment ispossible without a pressure gauge. When estimate the pressure, theestimation may take into account a reached-oxygen concentration by theoxygen concentration gauge or the reached-humidity measured by thehygrometer.

Adjustment of pressure is possible by various methods. If the FOUP to beused is known in advance, the volumes of the internal space Sf of theFOUP 7 to be used and the lid member of the FOUP 7 are determined.Therefore, the volume of the sealed space Sd is roughly predictable.Therefore, by filling the gas into the sealed space Sd for apredetermined period, at a predetermined flow rate, the pressure P2 ofthe sealed space Sd is adjustable to a predetermined pressure. In thiscase, a pressure gauge, an oxygen concentration gauge, and a hygrometerare not necessary for adjustment of the pressure.

In the above, a method of adjusting the pressure P2 is described. Thismethod however is also applicable to adjustment of the pressures P1 andP3. Further, the pressure adjustment may be done by adjusting the flowrates, adjustment by the equalizing valve, and a combination of flowrate adjustment and adjustment by equalizing valve. These mechanisms foruse in the pressure adjustment is collectively referred to as pressureadjuster.

In step S8, the door unit 81 and the lid member 72 are moved rearwardalong with the support frame 83, as shown in FIG. 13. This way, the lidmember 72 of the FOUP 7 is separated from the main body 71 thus openingthe internal space Sf, and the door unit 81 is separated from theopening portion 92 to open the casing 3 (internal space Se). At thistime, the abutting surface 71 b of the FOUP 7 is firmly attached to thewindow unit 90 through the O-ring 94, and hence the flowing-out andflowing-in of the gas are restrained between the area between the casing3 and the FOUP 7.

Further, since the pressure of the FOUP 7 is made high, there will be aflow of the gas from the internal space Sf of the FOUP 7 to the casing3. This restrains particles and the like in the casing 3 from enteringinto the FOUP 7, and keeps the inside of the FOUP 7 clean. It should benoted that continuous supply of the gas at a low flow rate through thesecond gas injection nozzle 44 c is also suitable for restraining theparticles from entering. The pressure adjustment is ended thereafter.

In step S9, the door unit 81 and the lid member 72 are moved downwardalong with the support frame 83, as shown in FIG. S14. This largelyopens the rear of the opening 71 a serving as an outlet/inlet port ofthe FOUP 7, thus enabling conveyance of a wafer W between the FOUP 7 andthe EFEM 1. Since the mechanism for moving the door unit 81 is entirelycovered by the cover 46, the gas inside the casing 3 is restrained fromleaking outside.

The operation at the time of opening the opening 71 a of the FOUP 7 isthud described above. To close the opening 71 a of the FOUP 7, the abovedescribed operations are performed in a reversed order. However, in anactual application of the door operation system, the above steps S6 andS7 may be omitted, provided that there is no problem in the pressure ofthe internal space Sf, the oxygen concentration, and the humidity, andthe like at the time of closing the opening 71 a of the FOUP 7.

By repeating the above operations, the O-rings 94 and 96 are resilientlyabutted to the lid member 72 or the door unit 81, which may lead tooccurrence of new particles. Such particles are however moved downwardby the downward flow formed inside the casing 3, when the lid member 72or the door unit 81 is opened. Therefore, the particles do not get onthe surface of a wafer W, keeping the surface of the wafer W in a cleanstate.

Characteristics of Load Port of the Present Embodiment

The load ports 4 of the present embodiment has the followingcharacteristics.

With the load port 4 of the present embodiment, even if the lid member72 of the FOUP 7 is inflated towards the base 41, the FOUP 7-side endsurface of the door unit 81 is positioned closer to the conveyance space9 than the FOUP 7-side end portion of the first seal member 94, when theFOUP 7 is attached to the opening portion 92. Therefore, the lid member72 and the door unit 81 do not contact each other. This prevents the lidmember 72 from contacting the door unit 81 and scattering fragments, andkeeps the space surrounding the load port 4 clean. Further, it ispossible to restrain an impact of contact from stirring up the dusts onthe door unit 81, or from shaking the FOUP 7 to stir up the dusts at thebottom portion of the FOUP 7 or deviate the position of accommodatedarticle from the proper position.

In the load port 4 of the present embodiment, the FOUP 7-side endsurface of the door unit 81 is at least partially positioned closer tothe conveyance space 9 than the FOUP 7-side end portion of the firstseal member 94 which is clamped and pressed against the base 41.Therefore, it is possible to reliably prevent contact of the lid member72 with the door unit 81, while the FOUP 7 is attached to the openingportion.

With the load port 4 of the present embodiment, it is possible toreliably prevent the lid member 72 from contacting the door unit 81,even if the lid member 72 of the FOUP 7 is inflated towards the base 41.

Characteristics of Door Operation System of the Present Embodiment

The door operation system of the present embodiment has the followingcharacteristics.

This door operation system or the load port 4 of the present embodimentincludes: the first gas injection nozzle 87 configured to inject gasinto the sealed space Sd formed between the FOUP 7 and the door unit 81while the FOUP 7 is in contact with the opening portion 92 via the firstseal member 94, i.e., while the FOUP 7 is attached to the openingportion 92, and the first gas discharge nozzle 88 configured todischarge gas from the sealed space Sd. With this, it is possible toremove the atmospheric air between the FOUP 7 and the door unit 81 andfill in the nitrogen gas (purge), while the FOUP 7 is attached to theopening portion 92. Therefore, atmospheric air between the FOUP 7 andthe door unit 81, which contains oxygen, moisture, particles and thelike that may cause a change in the characteristics of the wafer W suchas oxidation of the wafer W is prevented from entering the conveyancespace 9 or the FOUP 7 when the door unit 81 is opened. In other words,oxygen, moisture, and particles in the sealed space Sd can be eliminatedbefore opening the sealed space Sd by opening the lid member 72 of theFOUP 7. As a result, oxygen and the like do not leak into the FOUP 7 orthe conveyance space 9 when the lid member 72 is opened, which makes itpossible to maintain the cleanliness of the inside of the FOUP 7 and theconveying space 9.

In this door operation system of the present embodiment, the gasinjection operation by the first gas injection nozzle 87 and the gasdischarge operation by the first gas discharge nozzle 88 are repeated.Therefore, it is possible to reliably remove the atmospheric air betweenthe FOUP 7 and the door unit 81 and fill in a gas.

In the door operation system of the present embodiment, when clampingthe FOUP 7 to the base 41, the FOUP 7 is moved towards the door unit 81from the state where the door unit 81 and the lid member 72 are apartfrom each other. This way, the sealing performance between the FOUP 7and the base 41 through the O-ring 94 is improved.

In the door operation system of the present embodiment, the internalspace Sf of the FOUP 7 and the sealed space Sd are in communication witheach other, when the lid member 72 of the FOUP 7 is released. At thistime, a large pressure difference between P1 and P2 increases the flowrate of the gas moving between the FOUP 7 and the sealed space Sd, whichmay stir up particles accumulated on the bottom portion of the FOUP 7thus contaminating the wafers W. To address this, the P1 and P2 arecontrolled to be approximate each other, to reduce an amount of gasmoving between the FOUP 7 and the sealed space Sd. With this, scatteringof the particles is restrained, and hence contamination of the wafers Wis prevented.

With this load port 4 having the door operation system of the presentembodiment, the lid member 72 of the FOUP 7 is reliably detached at thetime of opening the opening portion 92, and the lid member 72 isattached at the time of closing the opening portion 92. Therefore, eachoperation is swiftly carried out.

Thus, the embodiment of the present invention is described hereinabove.However, the specific structure of the present invention shall not beinterpreted as to be limited to the above described embodiment. Thescope of the present invention is defined not by the above embodimentbut by claims set forth below, and shall encompass the equivalents inthe meaning of the claims and every modification within the scope of theclaims.

In the above-described embodiment, gas-purge is performed in step S6shown in FIG. 19, by having the first gas injection nozzle 87 supplynitrogen gas to the sealed space Sd, and having the first gas dischargenozzle 88 discharge gas from the sealed space Sd. However, the presentinvention is not limited to this, and the first gas discharge nozzle 88may perform discharge for reducing the pressure. Specifically, after theatmospheric air in the sealed space Sd is sucked out by the first gasdischarge nozzle 88 to reduce the pressure, the first gas injectionnozzle 87 supplies nitrogen gas. This way, a gas is filled in the sealedspace Sd efficiently.

In the above-described embodiment, the controlling unit Ct, the flowrate controller Cf, the drive controller Cd are installed in the EFEM 1.However, the present invention is not limited to this, and thecontrolling unit Ct, the flow rate controller Cf, and the drivecontroller Cd may be partially or entirely installed in the load port 4.In this case, the load port 4 is provided with a receiver unitconfigured to receive signals from a superordinate computer such as acontroller of the EFEM 1. In cases of installing the controlling unitsin the load port 4, the input end of the controlling unit Ct isconnected to the pressure gauges, the hygrometers, and oximeters for thesealed space Sd and the internal space Sf of the FOUP 7, and connectedto the flowmeters of the first gas injection nozzle and the second gasinjection nozzle, as shown in FIG. 27.

In the above-described embodiment, the pressure P1 of the internal spaceSf and the pressure P2 of the sealed space Sd are approximated with eachother in step 7 shown in FIG. 19. However, the present invention is notlimited to this, and where the pressure inside the conveyance space 9 isP3, the pressures P1, P2, and P3 may be approximated with one another.Specifically, based on one of P1, P2, and P3, the rest of two pressuresmay be adjusted. In this case, the time taken for adjusting the pressureis shortened by adjustment such that P2 and P3 approximate the pressureP1 of the internal space Se of the casing whose volume is largestamongst the sealed space Sd, the internal space Sf of the FOUP, and theinternal space Se of the casing. Alternatively, it is possible tocontrol the pressures so that the P1, P2, and P3 approximate apredetermined pressure value. The space sf of the FOUP 7, the sealedspace Sd, and the conveyance space 9 are in communication with oneanother, when the door unit 81 opens the opening portion 92. At thistime, a large pressure difference amongst each space increases the flowrate of the gas moving amongst the spaces, which may stir up particlesin the spaces. To address this, the P1, P2, and P3 are controlled to beapproximate one another, to reduce an amount of gas moving amongst theFOUP 7, the sealed space Sd, and the conveyance space 9. With this,scattering of the particles is restrained, and hence contamination ofeach space is prevented.

Further, instead of approximating the P1 and P2 with each other in stepS7, it is possible to adjust the pressures so that the P1, P2, and P3increases in this order. By controlling the pressures P1, P2, and P3 sothat they increase in this order, the pressure difference betweenadjacent spaces out of the space Sf in the FOUP 7, the sealed space Sd,and the conveyance space 9 is reduced. This reduces the flow rate of gasmoving between adjacent spaces, as compared to cases where pressuredifference between adjacent spaces is large, when the door unit 81 opensthe opening portion 92 to communicate spaces with one another.Therefore, an amount of gas moving amongst the sealed space Sd and theconveyance space 9 of the FOUP 7. With this, scattering of the particlesis restrained, and hence contamination of each space is prevented.

In the above-described embodiment, the FOUP 7 is adopted as thecontainer for conveying wafers. However, the wafer storage container isnot limited to this, and MAC (Multi Application Carrier), H-MAC(Horizontal-MAC), FOSB (Front Open Shipping Box), and the like may beadopted. Further, the container is not limited to a wafer storagecontainer, and the present invention is also applicable to a closedcontainer that accommodates an article, such as an electronic component,which is conveyed with an inert gas filled in the container.

Further, in the above-described embodiment, the load port is attached tothe EFEM. However, the present invention is also applicable to a sorterhaving a conveyance chamber for sorting accommodated articles in acontainer placed in a load port or exchanging an accommodating articlein a container in a load port with an accommodated article stored in acontainer in another load port, and applicable to a processing apparatusitself serving as a conveyance chamber, to which the load port isattachable.

The above-described embodiment adopted a clamp unit 50 having a cylinder52; however, the clamp unit is not limited to this. As shown in FIG.20A, a clamp unit 100 provided to a window frame 91 has a support piece101, and a rod-shaped pivot member 103 which is pivotably supported bythe support piece 101, and a motor 106 configured to drive the pivotmember 103. The support piece 101 extends forward from the window frame91, and pivotably supports the pivot member 103 at its hollow portion102 (see FIG. 21B). The pivot member 103 has pressing pieces 107 whichprotrude from the upper end portion and a middle portion relative to theaxial direction (see FIG. 20B). To the leading end of each of thepressing pieces 107, a pressing protrusion 108 is formed (see FIG. 22),and the flange portion 71 c of the FOUP 7 is clamped through thispressing protrusion 108. The motor 106 embedded in the horizontal baseportion 43 is connected to the lower end portion of the pivot member103, and rotates the pivot member 103 around its axis.

As shown in FIG. 21A, during an unclamped state, the pressing piece 107extends horizontally forward so as to be perpendicular to the windowframe 91 (see also FIG. 22A)). When the motor 106 drives and rotates thepivot member 103 from this state, the pressing piece 107 rotates aroundthe axis of the pivot member 103 as shown in FIG. 22B. By furtherrotating the pivot member 103, the pressing piece 107 presses the flangeportion 71 c through the pressing protrusion 108, thereby clamping theFOUP 7 (see also FIG. 20B). It should be noted that an air-driven camand the like may be adoptable in place of the motor 106 as a drivingunit for rotating the pivot member 103.

With the clamp unit 100 structured as above, it is possible to reducethe thickness of the clamp unit 100 relative to the front-rear directionthereof, and arrange the clamp unit 100 on the external space side.Therefore, interference with the wafer conveyance apparatus 2 operatedin the conveyance space 9 is prevented.

In the above-described embodiment, the FOUP 7-side end surface 81 c ofthe door unit 81 is entirely positioned closer to the conveyance space 9than the FOUP 7-side end portion of the O-ring 94. However, the FOUP7-side end surface 81 c of the door unit 81 may only be partiallypositioned closer to the conveyance space 9 than the FOUP 7-side endportion of the O-ring 94.

As shown in FIG. 23A, a recess 111 depressed towards the conveyancespace 9 is formed on an FOUP 7-side (front side) end surface 110 of thedoor unit 81. The bottom surface 112 of the recess 111 is positioned onthe conveyance space 9-side of the virtual line L1 indicating theposition of the FOUP 7-side end portion of the O-ring 94. In otherwords, the FOUP 7-side end surface 110 of the door unit 81 is at leastpartially (i.e., bottom surface 112) positioned closer to the conveyancespace 9 than the FOUP 7-side end portion of the first seal member 94.This brings about effects similar to those of the above-describedembodiment. At least partially herein indicates a part of the endsurface 110 of the door unit 81 nearby the center portion or an areaaround the center portion. Further, the concept of the end surface 110does not encompass the latch mechanism for fixing and releasing the lidmember 72 to/from the FOUP 7, the adsorption unit 79 for fixing the lidmember 72 to the door unit 81, and registration pins (not shown) forpositioning the lid member 72 to the door unit 81. On the other hand,the outer circumferential surface 113 on the outer circumference of theend surface 110 is positioned on the FOUP 7-side of the virtual line L1,due to the type of the FOUP 7 and the lid member 72 and accuracy errorat the time of manufacturing. It should be noted that the abuttingsurface 71 b of the FOUP 7 is positioned closer to the conveyance space9 than the lid member 72, the abutting surface 71 b abuts the O-ring 94and forms the sealed space Sd.

As shown in FIG. 23B, a curved surface 117 bowed towards the conveyancespace 9 is formed on an FOUP 7-side (front side) end surface 116 of thedoor unit 81. This curved surface 117 is positioned on the conveyancespace 9-side of the virtual line L1 indicating the position of the FOUP7-side end portion of the O-ring 94. In other words, the FOUP 7-side endsurface 116 of the door unit 81 is mostly positioned closer to theconveyance space 9 than the FOUP 7-side end portion of the first sealmember 94. This brings about effects similar to those of theabove-described embodiment. On the other hand, the outer circumferentialsurface 113 on the outer circumference of the end surface 116 ispositioned on the FOUP 7-side of the virtual line L1, due to accuracyerror at the time of manufacturing. It should be noted that a part ofthe FOUP 7 (lid member 72) is bowed towards the conveyance space 9.Further, the abutting surface 71 b of the FOUP 7 is positioned closer tothe conveyance space 9 than the outer circumference of the lid member72, the abutting surface 71 b abuts the O-ring 94 and forms the sealedspace Sd. As described, the shape of the curved surface 117 correspondsto an inflated surface 118 which is inflated by increasing the pressureinside the FOUP 7. Therefore, the FOUP 7 and the door unit 81 arereliably kept from contacting each other, even if the FOUP 7 inflates invarious shapes.

As shown in FIG. 24A showing a modification of FIG. 23A, it is possibleto adopt a structure in which the outer circumferential surface 113 ispositioned on the conveyance space 9-side of the virtual line L2, whilethe recess 111 is formed on the end surface 110 of the door unit 81. Inother words, the present modification deals with a case where the endsurface 110 of the door unit 81 is entirely positioned closer to theconveyance space 9 than the FOUP 7-side end portion of the first sealmember 94. This prevents interference of the lid member 72 with the doorunit 81, even when the lid member 72 is protruding towards theconveyance space 9, while allowing the abutting surface 71 b to abut thesealing member 94.

As shown in FIG. 24B showing a modification of FIG. 23B, it is possibleto adopt a structure in which the outer circumferential surface 113 ispositioned on the conveyance space 9-side of the virtual line L2, whilethe curved surface 117 is formed on the door unit 81. In other words,the present modification deals with a case where the end surface 110 ofthe door unit 81 is entirely positioned closer to the conveyance space 9than the FOUP 7-side end portion of the first seal member 94. Thisprevents interference of the lid member 72 having the inflated surface118 with the door unit 81, even when the lid member 72 is protrudingtowards the conveyance space 9, while allowing the abutting surface 71 bto abut the sealing member 94.

When the inflated lid member 72 is detached from the FOUP 7 by the doorunit 81, the inflated lid member 72 may return to its original state.When the end surface 110 of the door unit 81 is entirely positionedcloser to the conveyance space 9 than the first seal member 94 as incases shown in FIG. 24A and FIG. 24B, the lid member 72 may not beproperly fixed or attached to the FOUP 7, depending on the type of thelatch mechanism or the adsorption unit. In view of this, theseoperations may performed in a position closer to the FOUP 7 by apredetermined distance, than the position of releasing the fix of thelid member 72 with respect to the FOUP 7 and detaching the lid member 72from the FOUP 7. This predetermined distance is appropriately set basedon the expansion rate of the lid member 72 and the type of the latchmechanism and the adsorption unit.

In the above-described embodiment, the pressures are adjusted by usingthe first gas injection nozzle 87, the second gas discharge nozzle 88,the second gas injection nozzle 44 c, and the second gas dischargenozzle 44 d, which are separate from one another; however, the presentinvention is not limited to this.

As shown in FIG. 25 and FIG. 26, a first supply nozzle 120 that suppliesa gas is connected to the second gas injection nozzle 44 c. The secondgas discharge nozzle 44 d and the first gas injection nozzle 87 areconnected with each other via an intermediate nozzle 121. Further, thesecond gas injection nozzle 44 c and the second gas discharge nozzle 88are connected with each other via a connection nozzle 122. A midwayportion of the intermediate nozzle 121 is jointed with a second supplynozzle 123.

When the pressure P1 is higher than the P2, a first valve 125 and asecond valve 126 are opened, and a third valve 127 to a sixth valve 130are closed, as shown in FIG. 25. Therefore, the gas supplied from thefirst supply nozzle 120 flows into the FOUP 7 via the second gasinjection nozzle 44 c. The gas discharged from the FOUP 7 flows from thesecond gas discharge nozzle 44 d into the intermediate nozzle 121 viathe second valve 126. The gas is then supplied to the sealed space Sdvia the first gas injection nozzle 87, discharged from the second gasdischarge nozzle 88, and sequentially flows into the connection nozzle122 and the second gas injection nozzle 44 c. In the second gasinjection nozzle 44 c, the gas merges with a gas newly supplied from thefirst supply nozzle 120. With the gas flowing the above-describedpassage, the pressure P1 of the FOUP 7 and the pressure P2 of the sealedspace Sd approximate each other.

When the pressure P1 is lower than the P2, a fourth valve 128 and afifth valve 129 are opened, and the first valve 125 to the third valve127, and the sixth valve 130 are closed, as shown in FIG. 26. Therefore,the gas supplied from the second supply nozzle 123 via the fourth valve128 flows into the sealed space Sd via the intermediate nozzle 121 andthe first gas injection nozzle 87. The gas discharged from the sealedspace Sd sequentially flows in the second gas discharge nozzle 88 andthe connection nozzle 122, and then flows into the FOUP 7 via the secondgas injection nozzle 44 c. The gas discharged from the FOUP 7 isdischarged from the second gas discharge nozzle 44 d via the fifth valve129. With the gas flowing the above-described passage, the pressure P1of the FOUP 7 and the pressure P2 of the sealed space Sd approximateeach other. It should be noted that, in adjustment of the pressures P1and P3, only the third valve 127 arranged in the conveyance space 9 isopened. This communicates the FOUP 7 with the conveyance space 9 via thesecond gas injection nozzle 44 c and the connection nozzle 122, thusenabling equalization of pressures.

In the above-described embodiment, the nitrogen was used as an exampleof the inert gas; however, the gas is not limited to this, and anyintended gas such as a dry gas, argon gas, and the like are adoptable.

The above-described embodiment uses an O-ring as an example of the firstseal member 94 and the second seal member 96; however, the seal membersare not limited to these provided that sealing performance (sealability)is ensured.

As a seal member, a hollow seal member that expands or contracts bysupply or discharge of fluid may be adopted in place of the O-rings. Incases of adopting this hollow seal member as the first seal member 94,the FOUP 7 is firmly attached to the base 41 by inflating the hollowseal member, after the FOUP 7 is abutted against the base 41. Further,it is preferable to inflate the hollow seal member after clamping by theclamp unit 50, to further improve the firm attachment. This way, thesealing performance is improved by crushing the hollow seal member withthe force of the clamping, and the force of inflating the hollow sealmember.

The above-described embodiment deals with a case where the FOUP 7 ismoved towards the door unit 81, when clamping the FOUP 7 to the base 41,in step S4. Instead of this, it is possible to move the door unit 81forward to the lid member 72, from a state where the door unit 81 andthe lid member 72 are separated, after formation of the sealed space Sd(see FIG. 28). This forward movement is for bringing the door unit 81and the lid member 72 closer to each other and to bring the lid member72 into an unlatched state. Therefore, the door unit 81 may be movedforward to an extend that leaves a space between the lid member 72, orto an extent that the door unit 81 contacts the lid member 72. When thedoor unit 81 is moved forward to the lid member 72, the O-ring 96 ispressed and elastically deformed, thereby maintaining the sealed stateof the sealed space Sd.

In the above-described embodiment, the sealed space Sd is formed by thebase 41, the O-rings 94 and 95, the lid member 72, and the door unit 81.However, by adopting an O-ring 97 which is two O-rings 94 and 95 formedin one piece (see FIG. 29), the sealed space Sd may be formed by theO-ring 97, the lid member 72, and the door unit 81.

REFERENCE SIGNS LIST

-   3 casing-   7 FOUP (container)-   9 conveyance space-   41 base-   50 clamp unit (clamp)-   72 lid member-   81 door unit (door)-   87 first gas injection nozzle (first gas injection unit)-   88 first gas discharge nozzle (first gas discharge unit)-   92 opening portion-   94 O-ring (first seal member)-   96 O-ring (second seal member)-   Sd sealed space

The invention claimed is:
 1. A load port comprising: a base constitutinga part of a wall separating a conveyance space from an external space;an opening portion provided in the base, a door configured to open andclose the opening portion and to fix and release a lid member withrespect to a container accommodating therein an article; a first sealmember for sealing between the base and the container; a second sealmember for sealing between the base and the door; a sealed space definedby at least the first seal member, the second seal member, the lidmember, and the door while the container is in contact with the openingportion via the first seal member; a first gas injection unit configuredto inject an inert gas into the sealed space; a first gas discharge unitconfigured to discharge a gas including oxygen, moisture, and/orparticles from the sealed space through the door; a second gas injectionunit configured to inject an inert gas into the container; and a secondgas discharge unit configured to discharge an internal gas from thecontainer.
 2. The load port according to claim 1, further comprising: aplacement table on which the container is placed; and a window unitwhich is provided in a position to face the lid member of the containerplaced on the placement table and has the opening portion.
 3. The loadport according to claim 1, further comprising a placement table on whichthe container is placed, a housing space being formed between a coverprovided below the placement table and the base, and a door driverconfigured to drive the door being housed in the housing space.
 4. Theload port according to claim 1, further comprising a pressure adjustmentunit configured to adjust a pressure P1 of the container, a pressure P2of the sealed space, and a pressure P3 of the conveyance space, thepressure adjustment unit controlling P1, P2, and P3 to increase in thisorder.
 5. The load port according to claim 1, wherein, the pressure P2of the sealed space is adjusted by a pressure adjustment valve.
 6. Theload port according to claim 1, wherein, at least part of an end face onthe container side of the door is positioned on the conveyance spaceside of an end face on the container side of the first seal member. 7.The load port according to claim 1, further comprising a clamp unitconfigured to press the container toward the base while the container isattached to the opening portion.
 8. An EFEM comprising a conveyancespace and the load port according to claim 1 provided adjacent to theconveyance space, a gas with which the conveyance space is filled beingsucked through a suction port provided in a lower part of the conveyancespace and being circulated to an upper part of the conveyance spacethrough a circulation path.
 9. The EFEM according to claim 8, furthercomprising an equalizing member which equalizes pressures of the sealedspace and the conveyance space.
 10. The EFEM according to claim 9,wherein, the equalizing member includes an equalizing valve which isprovided on a passage by which the sealed space communicates with theconveyance space.
 11. The EFEM according to claim 10, wherein, the firstgas discharge unit includes a first gas discharge nozzle by which thesealed space communicates with the external space, the first gasdischarge nozzle is branched off to cause the sealed space tocommunicate with the conveyance space, and the equalizing valve isprovided at a branched part of the first gas discharge nozzle.